AutoCodes – GMC – P1339 2018 GMC Sierra

P1339 2018 GMC Sierra Code - Cylinder 2 Glow Plug Offset Exceeded Learning Limit

Quick Answer

The Glow Plug Control Module has not learned the glow plug offset values. Common causes include Perform Glow Plug Learn procedure, Faulty Glow Plug 2, Glow Plug 2 harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1339 2018 GMC Sierra indicates Cylinder 2 Glow Plug Offset Exceeded Learning Limit.
Common causes: Common causes include Perform Glow Plug Learn procedure, Faulty Glow Plug 2, Glow Plug 2 harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 320

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 30, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P1339 2018 GMC Sierra Description

The Glow Plug Control Module has not learned the glow plug offset values. If a glow plug has been replaced and the glow plug learn was not performed, or if the Glow Plug Control Module experiences an Electronically Erasable Programmable Read Only Memory (EEPROM) error or data corruption, this Diagnostic Trouble Code (DTC) to set. The DTC will be set if the glow plug hot resistance is outside a predefined threshold.

OBDII Code P1339 2018 GMC Sierra - Cylinder 2 Glow Plug Offset Exceeded Learning Limit - AutoCodes.com — P1339 2018 GMC Sierra Code - Cylinder 2 Glow Plug Offset Exceeded Learning Limit

What does this mean?

What are the Possible Causes of the DTC P1339 2018 GMC Sierra?

Perform Glow Plug Learn procedure
Faulty Glow Plug 2
Glow Plug 2 harness is open or shorted
Glow Plug 2 circuit poor electrical connection

How to Fix the DTC P1339 2018 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

If a Glow Plug was replaced, perform a Glow Plug Learn procedure with a Scan Tool.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1339 2018 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1339 2018 GMC Sierra code?

Need more information on how to fix the P1339 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1339 2018 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1339 2018 GMC Sierra Code

What does OBDII code P1339 mean on a 2018 GMC Sierra?

P1339 indicates that the Cylinder 2 Glow Plug Offset has exceeded the learning limit, meaning the engine control module (ECM) has detected an issue with the glow plug operation or its calibration on cylinder 2.

What are the symptoms of code P1339 on a 2018 GMC Sierra?

Common symptoms include difficulty starting in cold weather, increased exhaust smoke during startup, reduced engine performance, and an illuminated check engine light.

What causes the P1339 code to appear on a 2018 GMC Sierra?

Potential causes include a faulty glow plug in cylinder 2, damaged or corroded wiring or connectors, a malfunctioning glow plug control module, or incorrect calibration in the ECM.

Can I drive my 2018 GMC Sierra with a P1339 code?

While it may still be drivable, the vehicle may experience starting issues or reduced performance, especially in cold weather. Prolonged driving without addressing the issue could lead to further engine complications.

How do I diagnose the P1339 code on a 2018 GMC Sierra?

Diagnosis involves checking the glow plug in cylinder 2 for damage, testing the wiring and connectors for continuity, inspecting the glow plug control module, and verifying ECM calibration.

How can I fix the P1339 code on my 2018 GMC Sierra?

Repairs may include replacing the faulty glow plug in cylinder 2, repairing damaged wiring or connectors, replacing the glow plug control module, or reprogramming the ECM if calibration is incorrect.

How much does it cost to repair the P1339 code on a 2018 GMC Sierra?

Repair costs can vary, but replacing a glow plug typically costs $100â€“$200, while addressing wiring issues or replacing a control module may cost more depending on labor rates and parts.

What tools are needed to diagnose and repair the P1339 code?

Youâ€™ll need an OBDII scanner, a multimeter to test continuity, and potentially a glow plug removal tool. In some cases, specialized software may be required to reprogram the ECM.

Can a faulty glow plug cause long-term damage to my 2018 GMC Sierra?

Yes, a faulty glow plug can lead to poor combustion, increased emissions, and strain on the engine, especially in cold conditions, potentially causing further damage if not addressed.

Is the P1339 code specific to GMC vehicles?

No, while P1339 is common in GMC and Chevrolet diesel vehicles, it can appear in other vehicles with similar systems, but the definition and diagnostic steps may vary.